Earth formation sampling apparatus



Sept. 3, 1957 B. scHNEERsoHN 2,805,041

EARTH FORMATION SAMPLING APPARATUS Filed April 25, 1955 wjlrlld \\-l/// I. MIIIII [15mn INVENTOR BORIS SCH N EERSOH N l HIS ATTORNEYS collected fluid sample.

United States Patent y EARTH FORMATION SAMPLING APPARATUS Boris Schneersohn, Paris, France, assigner to Societe de Prospection Electrique Procedes Schlumberger, Paris, France, a corporation of France Application April 25, 1955, Serial No. 503,541 Claims priority, application France May 3, 1954 4 Claims. (Cl. 255-1.4)

The present invention relates to apparatus for obtaining samples of the contents of earth formations traversed by a well. More particularly, it has to do with new and improved apparatus of this character which enables uncontaminated samples to be obtained regardless of the relative pressure conditions in the formations and in the bore hole.

' The copending application Serial No. 386,279, tiled Octobery l5, 1953, for Apparatus for Sampling Fluids in Geological Formations discloses apparatus for obtaining samples of uids in geological formations, comprising a hollow projectile adapted to be projected against the formation (sidewall of the bore hole) from which a sample is desired and attached in a known manner by cables oisimilar means to the device which ejects it. This projectile has a forward cap member adapted to form a uidtight tit with the well wall. The cap member is provided with a frangible closure adapted to be destroyed on impact to Halford access for the formation fluid to a sample receiving chamber in the projectile. After the fluid receiving chamber is lled, a retaining valve closes and remains closed while the projectile is brought back to the surface of the earth. w

The retaining Valve inside the projectile is designed to function in response to differential pressure, so that as soon as a sample of the formation fluid has been received in the sample receiving chamber inside the projectile, the valve closes. Thereafter, on account of the differential pressure being exerted on its head, it maintains suiiicient force to prevent it from being subsequently opened during the return of the equipment .to the surface.

In a typical embodiment described in the aforementioned application, the retaining valve has a movable head in the chamber provided to receive and retain the In .fthe valve head is formed a cylindrical bore in which is snugly received a ixed piston member on which the valve head can slide relatively to the body of the projectile. Hence, the pressure exerted on the head of the valve by the fluid sample in the chamber will have the effect of pressing .the valve on its seat while overcoming the action of the difference in pressure exerted between the inside and outside of the chamber. Actually, this pressure is proportional to the dilierence between the pressure existing in the interior of the chamber containing the fluid sample and atmospheric pressure,

or a pressure on the order of atmospheric pressure, existing in the interior of the cylindrical bore in which the piston is received. While this apparatus is capable of giving good results, it is most effective in locations Where the uid pressure. in the formations to be sampled is not 'too much different from the fluid pressure in the bore hole.

It is an object of the present invention to provide new and improved sample taking apparatus of this general character which affords a perfect seal for the chamber containing'the stored liquid sample, regardless of the 2,805,041 Patented MSept. 3,V` 1957 fr 1C@vr relative conditions of pressure existing in the hole and in the earth formations.

This and other objects and advantages of the invention are attained by utilizing the difference between the pressure existing outside of the sample receiving chamber and atmospheric pressure (or a pressure of the same order as atmospheric pressure) as the differential pressure creating the force serving to press the valve on its seat, instead of using the dilference between the pressure inside .the sample receiving chamber and atmospheric pressure for this purpose, as in the earlier device described above. It follows then, that the greater the pressure existing outside the sample receiving chamber (i. e., in practice, the mud pressure) the greater will be the force caused by the dilferential pressure. Hence, by appropriately designing the surfaces where the different pressures acting on the valve are exerted, the force exerted on the head of said valve can be made suiiicient to insure absolute airtightness no matter what conditions of pressure exist. It is even possible to lower the equipment to bore hole levels where the-pressure of the mud is considerably higher than at the place where the samples were taken, without any reopening Vofthe valve.

In a preferred form of the invention, the head of the retaining valve carries a piston which is slidably received in a cylindrical bore in a member maintained in fixed relation to the projectile. Further, the piston Vis disposed outside of the sample receiving chamber in which a lluid sample hasbeen collected, so as to be acted upon by the pressure outside ofthe chamber. y

The invention may be better understood fromfthe following detailed description of a representative embodiment, taken in conjunction with the accompanying drawings in which:

Fig. l is a view in transverse section through a bore hole drilled into the earth,Y showing sample taker apparatus according to the invention positioned therein; and

Fig. 2 isla View in longitudinal section through a sarnple taker projectile constructed according to the invention.

Referring now to Fig. l, a bore hole 10 which usually contains water and mud 11 is shown traversing earth formations.12,-which may comprise, for example, sand filled Awith fluid (liquid or gaseous), a sample of which is desired. Within thebore' hole 10 is positioned lateral sample ltaking gun apparatus 13 in which a chamber 14 is formed. The chamber 14 constitutes a gun barrel for AVa sample taking projectile 15, which may be tired against Araised to the surface, the sampling projectiles 15 are pulled along with it by the cables 17 and are also brought to the surface. This arrangement is conventional in lat eral bore hole sampling devices. y

VAs shown in Fig. 2, the sampling projectile V15 comprises a hollow cylindrical body formedV of two parts 18 and 19, threaded one to the other to vfacilitate 'fabrication and assembly. Within the body is a sample receiving chamber 20 which is adapted `to receive a sample `of the uid through a port 21. The port 21, is normally closed by a retaining valve having a head member 22 provided with an upper surface 23 having a, groove 24 in which is tteda sealing ring25. The sealing ringV 25 i's adapted to be pressed against the forward' side wall of the chamber 20 so as to form a fluid-tight joint.

The head member 22 is formed with a cylindrical sur- Y face 26 which is slidably mounted in the port 21. The cyliiidri'cal surface 26 is pierced laterally by holes 27. Further, it is 'formed integral with a rod 28 carrying at its upper extremity a piston 29 having a lateral groove 30 for insertion of al sealing ring' 31. The piston 29 is adapted to slide in a cylindrical bore 32 formed'. in' a member 33 threadedly secured in a throat portion 34 communicating with the port 21. The member 33 is provided with orices 35 to permit the passage of the uid therethrough.

Formed on the part 18 is a stop 36 which serves to limit the movement of the valve 21 in the chamber 20.

On the forward end 37 of the body 19 there is shrink iitted a cap member 38, also of cylindrical shape, a cavity 39 being provided between the cap member 38 and the forward end 34 of the body 19. A sealing ring 40 insures fiuidtightness between the forward end 34 and the cap member 38.

The cap member 38 is made of a relatively soft metal such as pure aluminum, for example, and it has formed therein an orifice 41 closed by a frangible closure member 42 which` is integral therewith. The cap member 38 is of relatively large outside diameter and its forward portion 43 has a cross-section Which is, preferably, a truncated cone with a wide angle at the apex. The forward portion 43 of the cap member 38 has a groove 44 formed therein in which a sealing ring 45 is received'.

In operation, the sample taker 13 (Fig. l) is lowered into the bore hole to the desired level, and the pow` der charge 16 is set olf to project sample taking projectile in the known manner against the side wall o'f the bore hole. The sample taking projectile 15 penetrates relatively lightly into the bore hole side wall, as shown in dotted lines in Fig` l, the depth of the penetration depending on the nature of the Wall material. As `a result of the violent impact between the projectile 15 and the wall of the bore hole, the front portion 43 of the cap member 38 is deformed and is to some extent molded into the formation which constitutes the side wall of the bore hole, forming a tight joint with the side wall, This effect is considerably increased through the presence of the groove 44 and the sealing ring 45. At the same time, under the Aoutside pressure exerted on the closure 42, the latter shears and there follows an inrush into the chamber 46 of the substance (sand imbibed with fluid, for example) forming the side walls of the boring.

Because of the tight joint between the forward face of the cap member 38 and the wall of the bore hole,

the bore hole liquid 11 cannot reach the orifice 41.

Indeed, substantially only the materials derived from the formation itself, ever enter the chamber 46. The substances which have penetrated into this chamber under the effect of the strong pressure they exert, push back the valve 22, which, guided by the piston 29 and the surface 26 slides until it is brought to rest bythe stop member 36. In this position, the fluid freely. passes into the chamber 20 through the orifices, 27 until the chamber 20 is completely filled. Y 4

The recoil movement of the valve 22, which is limited by the stop member .36, creates a vacuum in the cavity located between the top of the piston 29 and the bore 32, so that when the chamber 20 is filled, the valve 22 closes again under the effect ofthe pressure exerted 9 in the chamber 46 on the under side ofy the piston 29. When the projectile is pulled out of the bore hole side wall, the pressure of the bore hole liquid is applied to the under side of the piston 29. The differential elect between the pressure of the bore hole liquid and the pressure inside the chamber between the top of the piston and the bore 32 is suicient in anystate and whatever. thc conditions, as has been previously stated, to keep the valve 22 tightly pressed on its seat, preventing lany inrush of bore hole liquid to the inside of the chamer 20. Y

It should also be noted that fluid tightness. is always insured by the ring 25. Further, the slide valve arrangement formed by the cylindrical portion 26 and the port 21 insures the lower centering of the valve, and, above all protects the ring 25 when there is an inrush of uid at great velocity into the chamber 20, it being understood that this ring is widely separated from the inside front wall of the projectile 15 which constitutes its seat, when the fluid begins to pass through the orices.

After the sample taker 13 has beenrbrought to the surface, the substances in the cavity 20 may be collected in any suitable manner. l

Of course, numerous variations can beA made in the typical embodiment described above without departing from the scope of the invention. In particular, the bore 32 in Fig. 2 might be formed in the valve head with the piston being carried by the member 33, provided that the piston cavity assembly is always situated outside the chamber 20 in which the fluid samples are collected. The invention, therefore, is not to be restricted to the specitic form shown Vby way of illustration, but comprehends all suchmodifications as come within the scope of the following claims.

I claim:

l. Apparatus for sampling the iiuid Icontent of geological formations and the like comprising a hollow tubular projectile adapted to be projected into a formation, mean-s forming a temporary 'closure for one end of saidV projectile, means forming a transverse partition in saidk projectile and cooperating with the other end portion of said projectile to form a fluid storage chamber, means forming an orice in said partition, valvek means normally closing said orifice, tubular skirt means on said valve means and slidably mounted in Isaid orifice, said skirt means having laterally directed openings formed therein, cooperating piston and bore means carried, by said valve means and by said projectile and bounding; a confined space, said piston and bore means being moved relative to one another when said valve means is opened to enlarge said confined space and being moved relative to one another when said valve means is closed to contract said confined space, and said cooperating piston and bore means being` responsive to fluid pressure outside of said chamber for developing force'tending to close said valve means.

2. In apparatus for samplingv the fluid lcontent of geological formations and the like which comprises a hollow tubular member closed at one end and' having an orifice at its other end and valve means for closing -said orifice, the combination of tubular skirt means on said valve means slidably mounted in said orilice and having laterally directed apertures formed therein, said apertures providing free communication between the interior and exterior of said tubular member when said valve means is opened, a support member mounted in fixed, relation to said tubular member in the vicinityV of said orice, cooperating piston mean-s and bore means carried by said valve means and by said support means and boundinga confined space, said piston means and bore means being moved relative to one another when said valvemeans is Vopened to enlarge said coniined spacel and being moved relative to onean- `otherrwhen said valve means is closed to contract said confined space, and said cooperating piston means and bore means being responsive to fluid pressure o utside said tubular member for developing a force tendingto close saidvalve means. Y Y Y l Y 3. In apparatus for sampling'the fluid content of geological formations and the like, the combination of a hollow tubular member Vclosed at one end and having a port at its other end tapering outwardly to an opening of larger 'size' than the port, valve means in said tubular member for closing said port, tubular skirt means on said Yvalvey means slidable in said port and having laterally directedfopenings formed therein providingy free communication between the interior and exterior of said tubular means when said valve means is opened, a support member mounted in said opening in said tubular member having passage means therein providing access to said port, cooperating piston and bore means carried by said valve means and by said support member and bounding a confined space, said piston means and bore means being moved relative to one another when said valve means is opened to enlarge a confined space and being moved relative to one another when said valve means is closed to contract said confined space, said cooperating piston means and bore means being responsive to fluid pressure outside said tubular member for developing a force tending to rclose said valve means, and a cap member tightly fitted at said other end of the tubular member, said cap member being formed with a frangible closure and cooperating with said other end of the tubular member to form a chamber in front of said tubular member.

4. In apparatus for sampling the uid content of geological formations and the like, the combination of a hollow tubular member closed at one end and having a port at its other end tapering outwardly to an opening of larger size than the port, valve means `in said tubular member for closing said port, sealing means for said valve means, tubular skirt means on said valve means slidable in said port and having laterally directed openings formed therein providing free communication between the interior and exterior of said tubular means when said valve means is opened, a support member mounted in said opening in said tubular member having passage means therein providing `access to said port, cylinder means carried by said support member, piston means carried by said valve means and slidable in said cylinder means in iiuid tight relation thereto, said piston means being moved outwardly and inwardly of said cylinder means when said valve means is opened and closed, respectively, said piston means being responsive to Huid pressure outside of said tubular member for developing force tending to close said valve means, stop means in said tubular member limiting opening movement of said valve means, and a cap member tightly fitted at said otherY end of the tubular member, said cap member being formed with a frangible closure and cooperating with said other end of the tubular member to form a chamber in front of said tubular member.

References Cited in the le of this patent UNITED STATES PATENTS 2,055,506 Schlumberger Sept. 29, 1936 2,288,210 Schlumberger June 30, 1940 2,214,551 Edwards Sept. l0, 1940 2,718,265 Conrad Sept. 20, 1955 

